Scottish Spiders Introduction to spiders Spiders are fascinating invertebrates found in a diverse range of habitats - from the inside of our homes to the tops of mountains. There are approximately 670 species of spider in the UK in 38 families - over 440 of these have been recorded in Scotland (from at least 28 different families). Spiders native to the UK have a great range of body sizes - from the tiny Minute maro money spider (Maro minutus) to the huge Cardinal spider (Tegenaria parietina) with a leg span of more than 10 centimetres. The Four-spot orbweaver (Araneus quadratus) is one of our heaviest weighing up to 2.5 grams! Spiders play an important ecological and environmental role controlling many insect pest species. Without them there would be more flies in your house and insects damaging our crops! Spiders and their relatives Spiders are arachnids and classified in the invertebrate Order Araneae. Arachnids not only include the spiders but also harvestmen (Order Opiliones), scorpions (Order Scorpiones), pseudoscorpions (Order Pseudoscorpiones), ticks (Order Ixodida) and mites (Order Acari). Almost all adult arachnids have four pairs of legs unlike adult insects which all have three pairs of legs. Arachnids have two further pairs of appendages, the jaws (chelicerae) which are adapted for feeding and defence and the pedipalps which have become adapted to aid in feeding, movement and reproduction. Harvestman Megabunus diadema Pseudoscorpion Neobisium carcinoides Harvestmen don’t produce silk! Very small - like to hitch a lift on other invertebrates! © Suzanne Burgess Burgess © Suzanne Trewella © Steve Red spider mite (Family Tetranychidae) Tick (Ixodes species) Group includes decomposers and parasitic species! Be tick aware when walking! © UH. Krisp © UH. © Ursula Smith Smith © Ursula Buglife—The Invertebrate Conservation Trust is a company limited by guarantee. Registered in England at The Lindens, 86 Lincoln Road, Peterborough, PE1 2SN. Company no. 4132695, Registered charity no, 1092293, Scottish charity no. SC040004 Scottish Spiders Spider anatomy Identifying male and female spiders Mature male and female spiders of each species have a unique and complex genital structure. Mature adults are often seen in autumn when males become more active looking for females to mate. Males – tips of pedipalps swollen in mature males Females – the epigyne of mature females is only and have complex structure to pass sperm to the revealed after the final moult as a complex female’s epigyne. Watch out for immature males feature at the top of the underside of the which have smooth swollen pedipalps and no hint abdomen. Not seen in immature females except of structure. sometimes a hint of the structure. Male wolf spider Pardosa amentata Garden spider Mature epigyne of Pardosa amentata (Araneus diadematus) © Steven Falk Falk © Steven Mature palp of Swollen palps Epigyne Pardosa amentata © Arno Grabolle Grabolle © Arno © Bernard A. Huber A. Huber © Bernard © Suzanne Burgess Burgess © Suzanne Buglife—The Invertebrate Conservation Trust is a company limited by guarantee. Registered in England at The Lindens, 86 Lincoln Road, Peterborough, PE1 2SN. Company no. 4132695, Registered charity no, 1092293, Scottish charity no. SC040004 Scottish Spiders How do spiders hunt? Spiders in the UK are all carnivorous, feeding on other insects and even other spiders, sometimes scavenging on already dead items! Spiders use different techniques when hunting for prey – they either spin a web to catch flying or passing prey, or they actively hunt and will sit and wait or stalk their prey. When spiders catch their prey they inject them with venom through the fangs of their chelicerae, this venom kills the prey. Some spiders go on to wrap their prey item in silk to feed on later. Spiders aren’t able to feed on solid items so need to reduce their prey to a liquid soup before feeding – they do this by secreting digestive juices into their prey. Species of Tegeneria (larger house spiders) have teeth on their chelicerae that they use to mash up solid prey items while adding the digestive juices to break it down, they are then able to suck up the mash they have created! Active hunters A large number of our 670 species of spiders don’t use a web to catch their prey but use more active techniques, they include the wolf spiders (Lycoside), ground spiders (Gnaphosidae), crab spiders (Thomisidae), jumping spiders (Salticidae) and woodlouse spiders (Dyseridae). Many of these have good eyesight, are fast runners and locate prey by detecting movement. Zebra spider (female) Wolf spider (female) Jumping spiders have four large forward facing eyes and stalk Wolf spiders have four large eyes and long legs for their prey– when they are within reach they jump. running using speed and strength to overcome prey. © Steven Falk © Steven © Steven Falk © Steven Xysticusspecies with Dysdera species soldier beetle with woodlouse Crab spiders wait on flowers for passing prey– they can Woodlouse spiders are nocturnal hunters with long legs over power insects much larger than themselves! and large forward projecting chelicerae to catch prey. © Roger Key © Roger Bradley © Darren Buglife—The Invertebrate Conservation Trust is a company limited by guarantee. Registered in England at The Lindens, 86 Lincoln Road, Peterborough, PE1 2SN. Company no. 4132695, Registered charity no, 1092293, Scottish charity no. SC040004 Scottish Spiders Spider silk and its uses All spiders produce silk from either two or three pairs of A female Four-spot orb weaver (Araneus spinnerets at the rear of their abdomen. Silk is produced as quadratus) in her silken retreat a liquid protein in the spider’s abdomen which solidifies to form threads - it is incredibly strong, flexible and elastic. By changing the speed at which silk is drawn from their spinnerets, spiders can create threads for different purposes - to create a web for catching prey, to create a retreat either in vegetation or a hole in a wall where they can wait for prey or guard eggs (see image on right) or females use silk to wrap around their eggs so she can carry © Suzanne Burgess © Suzanne her egg sac. Spider webs A small number of spiders make webs to catch prey. Although some are characteristic in shape and design it may not always be possible to identify the spider family from the web. Here are a few to look out for! Orb weaver web Sheet web Created by long-jawed orb weaver (Family Tetragnathidae) and Created by money spiders (Family Linyphiidae) and lesser Orb weavers (Family Araneidae) cobweb spiders (Family Hahniidae) © James K. Lindsey K. © James © Roger Key © Roger Tube web Funnel web Created by laceweb spiders (Family Amaurobiidae) and Created by funnel web spiders (Family Agelenidae) Tegenaria species of funnel web (Family Agelenidae) © Roger Key © Roger Burgess © Suzanne Buglife—The Invertebrate Conservation Trust is a company limited by guarantee. Registered in England at The Lindens, 86 Lincoln Road, Peterborough, PE1 2SN. Company no. 4132695, Registered charity no, 1092293, Scottish charity no. SC040004 Scottish Spiders Egg sacs and spiderlings Female spiders are caring parents! After they lay their eggs, all females wrap them in silk from their spinnerets creating an egg- sac. This protects the eggs from drying out, but also from predators and parasites. Female spiders will then guard this egg -sac either in a silken retreat or by carrying it until they hatch. On hatching, young spiderlings are similar in appearance to their parents– they grow by moulting their skins (known as ecdysis). The number of moults from when they hatch from the egg to becoming an adult varies between the different species. A female Cucumber spider (Araniella cucurbitina) Some female spiders will care for their young by carrying them guarding her egg-sac on their backs or by creating a nest for them. Burgess © Suzanne A female Nursery web spider (Pisaura mirabilis) carries her eggs sac under her A female wolf spider carrying her young abdomen and looks after the spiderlings when they hatch spiderlings on her abdomen © Suzanne Burgess © Suzanne © Steven Falk © Steven It is important that spiderlings disperse from their other siblings to reduce competition for food and space. For those cared for by females this dispersal will be once they have reached a specific size. Spiderlings disperse using two different mechanisms that both involve silk: • Ballooning - where the young spider moves to a high point and lifts its abdomen into the air and a strand of silk is drawn by the breeze from the spinnerets. • Rappelling - this relies on the strand of silk getting snagged on vegetation where the spiderling can use it as a bridge to cross to a new area. Sometimes when a large number of spiderlings disperse at the same time and land the silk strands combine and form gossamer across the vegetation as can be seen in the image below. © Darren Bradley © Darren Buglife—The Invertebrate Conservation Trust is a company limited by guarantee. Registered in England at The Lindens, 86 Lincoln Road, Peterborough, PE1 2SN. Company no. 4132695, Registered charity no, 1092293, Scottish charity no. SC040004 .